Ernest hofkinson



carryin Patented Oct. 2l, 1924.

UNITED STATES y 1,512,094 PATENT OFFICE.

ERNEST BoPxrNsoN, 0F NEW YORK, N. Y.

MANUFACTURE 0F TIRE CASINGS.

Application filed November 18, 1922. Serial No. 601,692.

To au whom it may concern:

Be it known that I, ERNEST HoeKiNsoN, a citizen of the United States, residing at New York city, county of New York, and State of New York, have invented certain new and useful Improvements in the Manu facture of Tire Casings, of which the following is a full, clear, and exact description.

This invention relates to the manufacture of tire casings, in particular their vulcanization. v

lt has been founddesirable in curing cas ings, especially those built on cores, to partially cure them without exerting a compacting pressure on their Walls, and subsequently to completely' cure the casings while maintaining a high compacting pressure thereon. This invention concerns such a process and aims to provide a new and improved method and apparatus for carrying on the same. More particularly, it aims to eliminate a difficulty, condensation, had with previously proposed practices, in the Viirst or partial curing stage, the steam heretofore employed often condensing and causing blemishes, or disiigurations, objectionable to the trade.

With the illustrated embodiment in mind and without iptenlioii to limit more than is required bythe prior art, the invention, briefly, consists in paftially vulcanizing the casings'with products of combustion which are supplied to a press containing a stack of loosely assembled moldsj/tnd tires on cores, thereafter completing .he vulcanization of ,the casings with a` me'fst, humid heating medium, suoli as stezafii, and with the sections of the mold clamped together under great pressure.

A preferred embodim nt of the invention is illustrated in the accompanying drawings, in which Fig. 1 is an elevation partly in section, diagrammatically illustrating apparatus for on the process;

And ig. 2 is cross-section through a mold, illustrating straight-side casing in the condition the arts are during partial curing'.

According to my invention, products of combustion interhingled with air to regulate the temperature of the mixture are conducted through a; duct 1, provided with a suitable valve 2, into a press 3, and eX- hausted therefrom at a suitable speed through a valve-controlled pipe 4, the inlet and outlet being located as desired to permit good circulation of the heated gases and maintenance of the vulcanizing temperature within the press. The press 3 may be of any suitable type, preferably having a mold moving means, or platen, 5, between which and the head 6, sectional molds 7 may be clamped, when desired, upon the walls of casings 8 mounted on cores 9. A valve-controlled inlet 10 and a valve-controlled outlet 11 are provided for introducing steam into the press, when desired.

As it is desirable to relieve the casings 'of a substantial compacting pressure during the partial curing treatment, the molds are loosely assembled and stacked upon one another in a p i'ess at the outset of the curing treatment. lVhile this may be done variously, I preferably insert collapsible lead pellets l2 between either, or both, the sections of the mold and the core, as illustrated.

For the combustion products, or gases, I preferably provide a furnace 13, having an elongated combustion chamber 14, at' one end of which is located an oil-burner 15, of any suitable type. Usually, this comprises an air-line 16 and an oil-line 17. Air for combustion maybe supplied through orifices 18 around the nozzle of the burner and also through a damper 19, controlling the passage of air into a pit 20 filled loosely with tire-brick, openings 21 being rovided to allow the air to enter the co. bustion chamber 14.' The combustion pr,I ucts-are removed from the rear of t e furnace through a relatively large pipe/"br duct 22, provided with a damper 23, be'vveen which and the press is located an air-iirlet 24, and a suction-fan 25. By' suitable regulation of the dampers 23 and 26, the latter in the airinlet, the suction device 25 may be relied upon to properly supply combustion prod ucts to the main 27. From the main 27, branches, such as the duct 1, may be provided for each of a. plurality of presses, if desired, and thereby the latter supplied with combustion products in an economical manner,

In operation, after loosely stacking the sectional molds 7 in a press, the latter is closed, as showmin Fig. 1, but without o erating the platen or ram, 5, to clamp t e moldsY together. rlhus, the casings in the sectional molds are substantially free of any substantial compacting pressure even when the collapsible device, or lead pellets, 12,'are made short enough in length to allow the mold sections to warmingly engage their rubber walls, as is desirable in some cases. The products of combustion from the furnace are then turned into the press chamber and passed therethrough to partially vulcanize the composition of the casings to the desired extent. The molds are comparatively cool at the outset of the operation and if stearr` weleturned into the heater at this tim., condensation would certainly occur and cause blemishes yon parts of the casings, especially the pockets in the lower sections of the'melds. `By supplying products of 4 combustion which are entirely, or almost entirely, free of moisture, this difficulty is avoided and the process made practical of performance in a vulcanizing press.

When the treatment with combustion products, or gases, has partly vulvanized the casings to the desired extent, the molds are closed so as te exert a powerful pressure upon the casings. This is done simply by operating the ram 5, in which case, of course, the collapsible lead pellets 12, if employed, are crushed, their ductile metal flowing/finto recesses, or pockets, 28, ofany suitable configuration, provided in the Amolds. ,Thereaften the casipgs are completely vulcanizedx by supplying steam through the inlet'lO to thepress, either at a high pressure, around 4() 4unds, if steam alone is to be used as'the, {iiiial heating medium, in which case the 'valve-ccntrolled lines l and 4 are cut off, or by supplyingvsteam at aboutv atmospheric pressure and commingling it combustion products to makethe latter humid and a better conductor of heat to the molds, in which case it is advantageous to introduce thea steam adjacent'the branch or duct l.

From, the foregoing, it will be seen that I have provided an extremely simple and practical device for carrying on a two-stage method of curin sometimes knowp..a's'"'tl`e set cure, in a rench type ofgpress that is in widespread use. The molds are only required to be handled once and the curing operations, or manipulations, are practicallv as simple as in the old straight'cure proi cedure.

lt will be obvious that many changes may be made in the procedure and apparatus without departure from the principles underlying the same, and reference should therefore be made to the accompanying claims for anunderstanding of the scope of the invention.

Having thus described my invention, what l claim and desire to protect by Letters Patent is:-- y

l. A method of curing tire casings in sectional molds which consists in, loading a vulcanizing press with tire casings in molds Whose sections are separated, subjecting the substantially free casiugs at first to the products of combustion from a furnace thereby partially curing them, and thereafter to steam While maintaining a compact ing pressure on the casings and completely curing the casings.

2. method of curing tire casings in sectional molds which consists in, loosely assembling tire 'casings on cores in sectional molds in a press, conducting products of combustion from a furnace and at a vulcanizing temperature through the press to partially cure the casings while the sections o the molds are collapsibly held separated, and iinally completing the vulcanizetion of the casings with steam while pressing the mold sections together to exert a compacting pressure on the casings.

3. A method of curing tire casings in sectional molds which consists in, stacking a plurality of sectional molds containing tire casings mounted on cores in a vulcanizing press and collapsibly supporting the mold sections and cores, inter-mingling air with combustion gases to control the temperature of the mixture and conducting the mixture through a, press-to partially cure the casings, and subsequently closing the molds compactingly upon the casings and completing;l 'their vulcanization by supply*- in a humid heatingmedium to the fpress.

igned at New York city county o New York, autisme of New York, this 16th day of November 1922.`

aNEsT HoPmNsoN. 

